Method of and a node device for transmitting a trigger message in a network of operatively interconnected node devices

Abstract

A method of, a node device and a computer program product arranged for transmitting a trigger message in a network of operatively interconnected node devices arranged along at least one elongated track is disclosed. The trigger message is configured for triggering a service provided by the node devices to a moving object. The node devices are divided into a plurality of groups, each group comprising, seen in a moving direction of the object, a first edge node device, at least one normal node device and a second edge node device, within each group at least the first edge node device and the second edge node device respectively comprising a sensor for detecting the object. The method comprises the step of: receiving, by a first edge node device in a group, a first object-approaching trigger message transmitted by a second edge node device in an immediate preceding group; and transmitting, by the first edge node device in the group, a second object-approaching trigger message to other node devices in the group. The method therefore ensures that only forward group trigger of the service is performed.